scholarly journals Dynamic Membrane Formation in Anaerobic Dynamic Membrane Bioreactors: Role of Extracellular Polymeric Substances

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0139703 ◽  
Author(s):  
Hongguang Yu ◽  
Zhiwei Wang ◽  
Zhichao Wu ◽  
Chaowei Zhu
Keyword(s):  
Extracellular Polymeric Substances ◽  
Membrane Bioreactors ◽  
Dynamic Membrane ◽  
Membrane Formation

scholarly journals Role of Mesh Pore Size in Dynamic Membrane Bioreactors

2021 ◽  
Vol 18 (4) ◽  
pp. 1472
Author(s):  
Pompilio Vergine ◽  
Carlo Salerno ◽  
Barbara Casale ◽  
Giovanni Berardi ◽  
Alfieri Pollice
Keyword(s):  
Pore Size ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Major Influence ◽  
Solid Retention Time ◽  
Dynamic Membrane ◽  
Effluent Quality ◽  
Set Up ◽  
High Suction

Two identical bench-scale Self-Forming Dynamic Membrane BioReactors (SFD MBR) were set-up and operated for the treatment of real urban wastewater. The two bioreactors were equipped with meshes of different mesh pore size. Meshes having pore size values of 20 and 50 µm were tested under solid retention time (SRT) of 15 d, whereas meshes with 50 and 100 µm pore sizes were compared under SRT of 50 d. The results of long-term experiments showed very good overall performances by all systems at the steady state. High flux (in the range 61–71 L m−2 h−1) and very good effluent quality were obtained, with average suspended solids and chemical oxygen demanding values below 10 mg L−1 and 35 mg L−1, respectively. The mesh pore size did not have a major influence on the average cleaning frequency. However, the pore size affected the effluent quality in correspondence of two particular conditions: (i) immediately after mesh cleaning; and (ii) during operation under high suction pressures (mesh clogging not promptly removed through cleaning). Moreover, the mesh cleaning frequency was observed to be dependent on the SRT. In tests with 50 d SRT, the cleaning requirements were very low (one every five days), and this limited the influence of the mesh pore size on the effluent quality. In conclusion, in SFD MBR, the role of the mesh pore size on the effluent quality may be more or less relevant depending on the operating conditions that directly influence the Dynamic Membrane formation.

Characteristics and role of dynamic membrane layer in anaerobic membrane bioreactors

2015 ◽  
Vol 113 (4) ◽  
pp. 761-771 ◽  
Author(s):  
Mustafa Evren Ersahin ◽  
Yu Tao ◽  
Hale Ozgun ◽  
Henri Spanjers ◽  
Jules B. van Lier
Keyword(s):  
Membrane Bioreactors ◽  
Dynamic Membrane ◽  
Membrane Layer ◽  
Anaerobic Membrane Bioreactors

scholarly journals Correction: Membrane fouling characteristics of membrane bioreactors (MBRs) under salinity shock: extracellular polymeric substances (EPSs) and the optimization of operating parameters

2021 ◽  
Author(s):  
Ling Luo ◽  
Hui Zhong ◽  
Ye Yuan ◽  
Wenwang Zhou ◽  
Changming Zhong
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Membrane Bioreactors ◽  
Operating Parameters ◽  
Salinity Shock ◽  
Fouling Characteristics

Correction for ‘Membrane fouling characteristics of membrane bioreactors (MBRs) under salinity shock: extracellular polymeric substances (EPSs) and the optimization of operating parameters’ by Changming Zhong et al., Environ. Sci.: Water Res. Technol., 2021, DOI: .

Correlation between membrane fouling and soluble/colloidal organic substances in membrane bioreactors for municipal wastewater treatment

2005 ◽  
Vol 51 (6-7) ◽  
pp. 1-8 ◽  
Author(s):  
B. Lesjean ◽  
S. Rosenberger ◽  
C. Laabs ◽  
M. Jekel ◽  
R. Gnirss ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Membrane Bioreactors ◽  
Size Exclusion ◽  
Water Phase ◽  
Parallel Operation ◽  
Municipal Wastewater Treatment ◽  
Operational Conditions ◽  
The Difference

Two similar membrane bioreactors of 2 m3 each were operated in parallel over two years under the same operational conditions, fed with the same municipal wastewater. The only process and operational difference between both pilot plants was the position of the denitrification zone (pre-denitrification in pilot 1 and post-denitrification in pilot 2). Despite parallel operation, the two MBRs exhibited different fouling rates and decreases in permeability. These differences could not be accounted for by MLSS concentrations, loading rates, or filtration flux. In a one-year investigation, soluble and colloidal organic material in the activated sludge of both MBR was regularly analysed by spectrophotometric and Size Exclusion Chromatography (SEC) methods. The larger organic molecules present in the sludge water phase (i.e. polysaccharides, proteins and organic colloids) originating from microbial activity (extracellular polymeric substances) were found to impact on the fouling and to explain the difference in membrane performance between the two MBR units. In both pilot plants, a linear relationship could be clearly demonstrated between the fouling rate of the membrane and the concentration of polysaccharides in the sludge water phase during a 5 month operational period at an SRT of 8 days.

scholarly journals Organic Stabilization of Extracellular Elemental Sulfur in a Sulfurovum-Rich Biofilm: A New Role for Extracellular Polymeric Substances?

2021 ◽  
Vol 12 ◽  
Author(s):  
Brandi Cron ◽  
Jennifer L. Macalady ◽  
Julie Cosmidis
Keyword(s):  
Crystal Structures ◽  
Extracellular Polymeric Substances ◽  
Elemental Sulfur ◽  
Dense Matrix ◽  
Cave System ◽  
Carboxylic Groups ◽  
Sulfur Oxidizing ◽  
New Evidence ◽  
Sulfur Oxidizing Bacteria

This work shines light on the role of extracellular polymeric substance (EPS) in the formation and preservation of elemental sulfur biominerals produced by sulfur-oxidizing bacteria. We characterized elemental sulfur particles produced within a Sulfurovum-rich biofilm in the Frasassi Cave System (Italy). The particles adopt spherical and bipyramidal morphologies, and display both stable (α-S8) and metastable (β-S8) crystal structures. Elemental sulfur is embedded within a dense matrix of EPS, and the particles are surrounded by organic envelopes rich in amide and carboxylic groups. Organic encapsulation and the presence of metastable crystal structures are consistent with elemental sulfur organomineralization, i.e., the formation and stabilization of elemental sulfur in the presence of organics, a mechanism that has previously been observed in laboratory studies. This research provides new evidence for the important role of microbial EPS in mineral formation in the environment. We hypothesize that the extracellular organics are used by sulfur-oxidizing bacteria for the stabilization of elemental sulfur minerals outside of the cell wall as a store of chemical energy. The stabilization of energy sources (in the form of a solid electron acceptor) in biofilms is a potential new role for microbial EPS that requires further investigation.

scholarly journals The Role of New Inorganic Materials in Composite Membranes for Water Disinfection

Membranes ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 101 ◽  
Author(s):  
Roberto Castro-Muñoz
Keyword(s):  
Composite Membranes ◽  
Membrane Bioreactors ◽  
Polymeric Membranes ◽  
Inorganic Materials ◽  
Water Disinfection ◽  
Biologically Active ◽  
Separation Performance ◽  
Nanofiltration Membrane ◽  
Physical And Chemical

Today, there is an increasing interest in improving the physicochemical properties of polymeric membranes by merging the membranes with different inorganic materials. These so-called composite membranes have been implemented in different membrane-based technologies (e.g., microfiltration, ultrafiltration, nanofiltration, membrane bioreactors, among others) for water treatment and disinfection. This is because such inorganic materials (such as TiO2-, ZnO-, Ag-, and Cu-based nanoparticles, carbon-based materials, to mention just a few) can improve the separation performance of membranes and also some other properties, such as antifouling, mechanical, thermal, and physical and chemical stability. Moreover, such materials display specific biological activity towards viruses, bacteria, and protozoa, showing enhanced water disinfection properties. Therefore, the aim of this review is to collect the latest advances (in the last five years) in using composite membranes and new hybrid materials for water disinfection, paying particular emphasis on relevant results and new hydride composites together with their preparation protocols. Moreover, this review addresses the main mechanism of action of different conventional and novel inorganic materials toward biologically active matter.

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